Recovery of vehicle exhaust heat otherwise expelled from a vehicle can improve the efficiency of various vehicle systems and improve fuel economy. For example, vehicle exhaust heat has been used to warm engine coolant, especially after a cold start of the engine. Furthermore, a thermoelectric generator can be integrated into a vehicle exhaust system to produce electrical energy from a temperature differential created by the exhaust heat. However, thermoelectric generators are sensitive to overheating, so exhaust heat flow to the thermoelectric generator must be limited when temperature of the thermoelectric generator approaches or reaches a maximum operating temperature.